Accessibility Guidelines Related to a Web Site's Cascading Style Sheets (CSS)
Along with the Web site's code, the cascading style sheets should also be valid.
Validate the code and CSS using a code validation tool (i.e. W3C's Markup Validation Service).
WCAG Guidelines referenced:
- Guideline 4.1 Compatible: Maximize compatibility with current and future user agents, including assistive technologies.
4.1.1 In content implemented using markup languages, elements have complete start and end tags, elements are nested according to their specifications, elements do not contain duplicate attributes, and any IDs are unique, except where the specifications allow these features. (Level A)